Scientists Discover New Regulatory Component in Infectious Bacterium

Danielle Garsin, PhD, Sruti DebRoy, PhD, and Ambro van Hoof, PhD, are working to further the understanding of how bacteria survive and cause disease.

The discovery of a new regulatory component in an infectious bacterium could aid efforts to explain its ability to survive in the human body, report microbiologists at the University of Texas Health Science Center at Houston (UTHealth) and University of Maryland, College Park, in the journal Science.

The scientists analyzed a bacterium called Enterococcus faecalis that is found in the gut of most adults. While in healthy people this bacterium is normally benign, certain strains can cause severe disease when they contaminate non-intestinal sites. It is a leading cause of health care-associated infection.

“We are trying to learn more about the interaction between E. faecalis and the host,” says Danielle Garsin, PhD, co-senior author and associate professor in the Department of Microbiology and Molecular Genetics at the UTHealth Medical School. “Our goal is to understand how key genes and processes are regulated in this pathogen. This information may lead to the development of novel therapeutics.”

Garsin’s research focused on a compound called ethanolamine (EA) that is potentially used by E. faecalis to survive in the human body. While the ability of E. faecalis to utilize EA was known, how the bug regulates the genes involved was not completely understood.

The scientists identified a novel regulatory component that was key to turning on the genes involved in EA metabolism under the right conditions. When researchers blocked the regulatory component, the molecular machinery was produced inappropriately.

“Not only does this regulatory component help explain how this particular process is controlled in E. faecalis, its discovery and elucidation increases our understanding of the variety and diversity of regulatory mechanisms in bacteria,” Garsin says.

Also contributing to the study was Arati Ramesh, PhD, of the Department of Biochemistry at The University of Texas Southwestern Medical Center in Dallas.

The study titled “A riboswitch-containing sRNA controls gene expression by sequestration of a response regulator” received support from National Institutes of Health grants (R01AI076406, R56AI110432 and R01GM099790), a National Science Foundation grant (MCB-1051440) and a Welch Foundation grant (AU-1773).